Oligomerization of conjugated dienes



United States Patent 3,393,245 OLIGOMERIZATION OF CONJUGATED DIENESErnest A. Zuech, Bartlesville, Okla, assignor to Phillips PetroleumCompany, a corporation of Delaware No Drawing. Continuation-impart ofapplication Ser. No. 500,226, Oct. 21, 1965. This application Apr. 11,1966,

Ser. No. 541,516

3 Claims. (Cl. 260-666) ABSTRACT OF THE DISCLOSURE Conjugated dienes areoligomerized or reacted with ethylene using a catalyst formed from aconjugated dieneorganolithium adduct and a nickel compound, cobaltcompound, or iron compound.

This application is a continuation-in-part of my copending applicationSer. No. 500,226, filed Oct. 21, 1965, now abandoned.

This invention relates to a new and improved process for polymerizingconjugated dienes. In one aspect this invention relates to a new andimproved catalyst for polymerizing conjugated dienes. Another aspectrelates to a new and improved process for forming diolefins. Anotheraspect relates to a new and improved catalyst for forming diolefins.

Heretofore processes and catalysts have been proposed for making linearand cyclic dimers and trimers of conjugated dienes. However, theseprocesses and catalysts have, in general, failed to yield substantialamounts of the desired dimers and/ or trimers.

It has now been found that butadiene can be oligomerized to producemethylheptatriene in high yields by contacting butadiene underoligomerization conditions with a catalyst formed on mixing abutadiene-organolithium adduct with a cobalt compound. Byoligomerization is meant the reaction and therefore polymerization ofrelatively few units of a polymerizable material. By oligomers is meantrelatively low molecular weight polymerized materials. Dimers andtrimers are typical oligomers.

The catalyst according to this aspect of the invention is that formed onmixing a butadiene-organolithium adduct, which itself is formed byreacting butadiene with an organolithium compound, and a cobaltcompound.

It has also been found that a conjugated diene selected from the groupconsisting of butadiene, isoprene, and piperylene, can be oligomerizedto produce cyclododecatrienes in high yields by contacting one of theabove conjugated dienes under oligomerization conditions with a catalystformed on mixing a conjugated diene-organolithium adduct with a nickelcompound.

The catalyst for this aspect of the invention is that formed on mixing aconjugated diene-organolithium adduct, which itself is formed byreacting one of butadiene, isoprene, or piperylene with an organolithiumcompound, with a nickel compound.

It has also been found that at least one conjugated diene selected fromthe group consisting of butadiene, isoprene, and piperylene can bereacted with ethylene to form diolefins, by contacting ethylene and theabove conjugated dienes under reaction conditions with a catalyst formedon mixing a conjugated diene-organolithium adduct with one of an ironcompound, a nickel compound, and a cobalt compound.

The catalyst for this aspect of the invention is that formed on mixing aconjugated diene-organolithium adduct, which itself is for-med byreacting one of butadiene, isoprene, or piperylene with an organolithiumcompound, with one of an iron compound, a nickel compound, and a cobaltcompound.

3,393,245 Patented July 16, 1968 Accordingly, it is an object of thisinvention to pro vide a new and improved polymerization process forconjugated dienes.

It is another object of this invention to provide a new and improvedcatalyst for polymerizing conjugated dienes.

It is another object of this invention to provide a new and improvedprocess for making diolefins.

It is another object of this invention to provide a new and improvedcatalyst for forming diolefins.

Other aspects, objects, and the several advantages of this inventionwill be apparent to those skilled in the art from the description andthe appended claims.

The organolithium compounds useful for forming the adduct component ofthe catalyst of this invention are represented by the formula RLiwherein R is selected from the group consisting of saturated aliphatic,saturated cycloaliphatic, aromatic, and combinations of these radicalsand has from 2 to 14, preferably 12, carbon atoms, inclusive, andwherein x is a whole integer of 1, 2, or 3. Preferred organolithiumcompounds are lithium alkyl compounds having from 2 to 6 carbon atomsper molecule.

Representative examples of organolithium compounds that can be employedare: ethyllithium, n-butyllithium, isopentyllithium, n-octyllithium,isononyllithium, n-dodecyllithinm, cyclohexyllithium,cycloheptyllithium, cyclodecyllithium, cyclododecyllithium,1,2-dilithioethane, 1,4-dilithiobutane, 1,6-dilithiooctane,1,5-dilithiodecane, 1,4-dilithiododeeane, 1,2-dilithiocyclohexane,1,4-dilithiocyclooctane, l,S-dilithiocyclohendecane,1,3,5-trilithiopentane, 2,4,6-trilithiononane,1,3,5-trilithiocyclohexane, 1,3,S-trilithiocyclodecane, mono-, di-, andtrilithiobenzene, mono-, di-, and trilithionaphthalene, dilithiostilbene(1,2- dilithio-1,2-diphenylethane), and the like.

The adduct is formed by reacting at least one of the above organolithiumcompounds with at least one of butadiene, isoprene, and piperylene, theorganolithium compound thereby adding to the conjugated diene. Forexample, butyllithium can add to butadiene in a conventional 1,4 mannerthereby adding a butyl radical to the 1 carbon atom of a butadienemolecule and adding a lithium atom to the 4 carbon atom of the butadienemolecule.

The formation of the adduct is carried out by contacting theorganolithium compound(s) with the conjugated diene at a temperaturegenerally in the range of from about 10 to about 80, preferably fromabout 0 to about 40 C. for a period of time sufiicient to effectsubstantially complete formation of the desired adduct. The reaction canvary widely but will generally be from about 10 minutes to about 24hours. The mole ratio of butadiene to molar equivalent of lithiumemployed will generally range from about 1/1 to about 25/1, althoughhigher ratios can be employed if desired, the highest ratio employedbeing determined by economics rather than functionality. Generally,sufiicient conjugated diene should be employed to insure completereaction of the organolithium compound. The pressure employed in formingthe adduct will be that sufficient to maintain the reactantssubstantially in the liquid phase. The pressure employed can beautogenous or higher if desired using conventional pressurizingmaterials such as nitrogen and the like.

The formation of the adduct can be carried out in the presence orabsence of conventional, inert diluents. When diluents are employed,ethers, hydrocarbons and mixtures of two or more of each or both groupsare preferred. The ethers employed generally should contain from 4 to 10carbon atoms per molecule, inclusive, and can include ethyl ether,tert-butyl ether, propyl ether, pentyl ether, tetrahydrofuran, dioxane,and the like. When hydrocarbons are employed they can be selected fromthe group consisting of aliphatic, cycloaliphatic, aromatic,

- (acetylacetone),

and combinations thereof having from 4 to 10 carbon atoms, inclusive.Examples of these include n-butane, npentane, isopentane, nhexane,n-heptane, isooctane, ndodecane, cyclohexane, methylcyclohexane,cyclooctane, benzene, toluene, xylene, Decalin, and the like.

The adduct is then combined with a cobalt compound or a nickel compoundor an iron compound in the presence or absence of diluents, preferablyin the presence of diluents. If diluents are employed they can beselected from the group of diluents discussed hereinabove with referenceto the formation of the adduct component of the catalyst. Suitablenickel, iron, and cobalt compounds include the halides, salts of mono-,di-, and tribasic organic acids containing from 2 to 20 carbon atoms permolecule, and chelates of B-diketones of the formula H RCC-R t t twherein R is at least one radical selected from the group consisting ofsaturated aliphatic, saturated cycloaliphatic, aromatic radicals, andcombinations thereof and contain ing from 1 to 10 carbon atoms,inclusive.

Although for the sake of brevity, the following list of examples ofcompounds will be limited to cobalt, it is to be understood that foreach cobalt compound listed the equivalent nickel or iron compounds canalso be employed in this invention. Suitable compounds include cobaltchloride, cobalt bromide, cobalt iodide, cobalt acetate, cobaltpropionate, cobalt benzoate, cobalt oxalate, cobalt phthalate, cobaltcaproate, cobalt pelargonate, cobalt laurate, cobalt myristate, cobaltstearate, cobalt arachidate, and cobalt salts of 2,4-pentane dione 3,5heptanedione, 11,13 tricosanedione, 1,3 dicyclohexyl 1,3 propanedione,1,5- dicyclopentyl 2,4 pentanedione, 1,3 diphenyl 1,3- propanedione, 1,5diphenyl 2,4 pentanedione, 2,8- dimethyl 4,6 nonanedione, 1,3 di(4 nbutylphenyl) 1,3 propanedione, 1,11 diphenyl 5,7- hendecanedione, 1phenyl 1,3 butanedione, 2,4- decanedione and 1 (3,5 dimethylcyclohexyl)2,4 pentanedione; and the like. In addition, when nickel compounds areemployed the nickel salt of dimethylglyoxime (2,3 butanedione dioxime)can be used.

Preferred compounds include nickelous chlorine, nickelous bromide,nickelous iodide, nickelous fluoride, nickelous acetate, nickelousbenzoate, nickelous oxalate, nickelous stearate, ferrous chloride,ferric bromide, ferrous iodide, ferric acetate, ferric propionate,ferrous butyrate, ferric caproate, ferrous oxalate, ferrous phthalate,ferric laurate, ferric stearate, cobaltous bromide, cobaltous iodide,cobaltic acetate, cobaltous propionate, cobaltous benzoate, cobalticoxalate, cobaltous phthalate, cobaltous caproate, cobaltic pelargonate,cobaltous laurate, cobaltous myristate, cobaltous stearate, cobaltousarachidate. Other preferred compounds include cobaltic, cobaltous,nickelous, ferrous, and ferric salts of 2,4 pentanedione(acetylacetone), 3,5 heptanedione, 11,13 tricosanedione, 1,3dicyclohexyl 1,3- propanedione, 1,5 dicyclopentyl 2,4 pentanedione, 1,3diphenyl 1,3 propanedione, 1,5 diphenyl 2,4- pentanedione, 2,8 dimethyl4,6 nonanedione, 1,3- di(4 n butylphenyl) 1,3 propanedione, 1,11diphenyl 5,7 hendecanedione, 1 phenyl 1,3 butanedione, 2,4 decanedioneand 1 (3,5 dimethylcyclohexyl) 2,4 pentanedione; and the like.

The contact of the adduct with the cobalt or nickel or iron compound canbe carried out at a temperature from about 80 to about 80, preferablyfrom about to about 25 C. The time for contacting will vary widely butwill generally be from a few minutes, e.g. 3, to several hours, e.g. 3.The ratio of the adduct to the nickel or cobalt or iron compound willgenerally be in the range of from 2/1 to 6/1, preferably 2/1 to 9/1 forthe iron compound, molar equivalents of lithium per mole of cobalt ornickel or iron. The organolithium compound should be present in anamount which is stoichiometrically sufficient to cause substantiallycomplete reduction to zero valence of the cobalt or nickel or iron asthe case may be. For example, the reduction of cobalt bromide wouldrequire 2 molar equivalents of lithium per mole of cobalt bromide, whilethe substantial reduction of cobalt acetylacetonate would require atleast 6 molar equivalents of lithium per mole of cobalt acetylacetonate.In similar fashion, for complete reduction, nickel chloride requiresabout 2 molar equivalents, ferric chloride about 3 molar equivalents,and ferric acetylacetonate about 9 molar equivalents. The presence oflithium adduct in excess of that required to reduce the nickel or cobaltor iron to a zero valence state and to reduce any carbonyl groupspresent should be avoided in order to prevent excessive polymerizationof the diene monomer to relatively heavy polymeric products.

The pressure employed in this step of the catalyst formation Willgenerally be that sufficient to maintain the reactants substantially ina liquid state and can be autogenous or higher if desired.

The dimerization of butadiene to a linear oligomer using the cobaltcatalyst of this invention can be carried out at temperatures in therange of from about 10 to about 200, preferably from about 20 to about150 C. for a period of time sufiicient to effect the desireddimerization. Generally the time for reaction can vary widely but willbe from about 10 minutes to about 100 hours. The dimerization is carriedout under a pressure sufficient to keep the reactants substantiallyliquid which can be autogenous or higher if desired. The dimerizationcan be carried out in the absence or presence of a diluent, preferablyin the presence of at least one diluent described hereinabove withreference to the formation of the adduct. The amount of catalystemployed will be that which provides from 0.1 to 10 atoms of cobalt per1000 moles of conjugated diene.

The product of this dimerization process, when butadiene is the feed,comprises oligomers and is composed primarily of3-methyl-1,4,6-heptatriene which can be recovered by conventionalmethods such as fractional distillation, crystallization, solventextraction, chromatographic techniques and the like. It is sometimesconvenient to contact the reaction mass with aqueous mineral acid todestroy the catalyst and separate the catalyst components from theoligomer-containing organic p ase.

The trimerization of butadiene, isoprene, or piperylene with a nickelcatalyst of this invention to form cyclic oligomers and thepolymerization of those conjugated dienes with the iron catalyst of thisinvention can both he carried out at a temperature in the range of fromabout to about 200, preferably from about to about C. for a period oftime sufiicient to effect the desired trimerization. Generally, the timefor reaction will be from about 10 minutes to about 24 hours. Thetrimerization can be carried out in the absence or presence of adiluent, preferably in the presence of at least one diluent describedhereinabove with reference to the formation of the adduct component ofthe catalyst. The pressures employed during this reaction should be thatsufficient to maintain the reactants substantially in the liquid phaseand can be autogenous or higher if desired. The amount of catalystemployed in the trimerization reaction will be that which provides fromabout 0.1 to about 10 atoms of nickel per 1000 moles of conjugateddiene.

The product of this trimerization reaction comprises oligomers and iscomposed primarily of cyclododecatrienes which can be recovered such asfractional distil lation, crystallization, solvent extraction,chromatographic techniques and the like.

The conversion of conjugated dienes together with ethylene to diolefinsusing the iron, nickel or cobalt contaning catalysts of this inventioncan be carried out at temperatures in the range of from about 0 to about100, preferably from about 25 to about 60 C. for a period of time toeffect the desired reaction. The time can vary widely but will generallybe in the range of from about minutes to about 100 hours. The reactionis carried out under a pressure sufficient to keep the reactantssubstantially in the liquid state which can be autogenous and can varyup to about 1000 p.s.i.g. or higher. The pressure of the reaction can beadjusted by the ethylene comonomer. Sufiicient ethylene should bepresent in the reaction zone to provide at least a 1 to 1 mole ratio ofethylene to butadiene, with an excess of ethylene presently beingpreferred. The reaction can be carried out in the presence or absence ofa diluent, preferably in the presence of at least one diluent describedwith reference to the formation of the catalyst. The amount of catalystemployed will vary widely but will generally range from about 0.1 toabout 10 atoms of iron per 1000 moles of conjugated diene present.

The linear diolefin product, when 1,3-butadiene and ethylene are reactedover the iron-containing catalyst of this invention, is principally1,4-cis-hexadiene with some 2,4-hexadiene being present. The products ofthis aspect of the invention can be recovered by conventional methodssuch as distillation, crystallization, solvent extraction, adsorptiontechniques, and the like. It can be convenient to contact the reactionmass with aqueous mineral acid to destroy the residual catalyst andseparate the catalyst components from the product-containing organicphase.

Example I A catalyst was prepared by reacting 0.02 mole of nbutyllithiumwith grams (0.28 mole) of butadiene in 50 milliliters of cyclohexane.After 30 minues at C. the reaction mixture was added to a suspension of1.28 grams (0.005 mole) of cobalt acetylacetonate in 25 milliliters ofcyclohexane which was cooled in an ice bath.

' After minutes, the above-prepared catalyst was then charged to al-liter autoclave along with 123 grams (2.28 moles) of butadiene. Theautoclave was heated to 60 C. at which temperature the pressure was 90p.s.i.g. After 2 hours and 25 minutes the pressure had dropped to 25p.s.i.g. and at this time the autoclave heaters were turned off. Theunreacted butadiene was vented from the autoclave and the liquidreaction mixture in the autoclave was contacted with a 5 weight percentaqueous solution of hydrochloric acid. The organic phase was thenseparated and distilled to produce 62.1 grams of material boiling fromto 73 C. at 125 millimeters mercury absolute pressure which material wasidentified by gas liquid chro matography to be essentially3-methyl-1,4,6-heptatriene. The distillation also yielded 32.6 grams ofmaterial boiling from 75 C. at 50 millimeters mercury absolute pressureto 86 C. at 3 millimeters mercury absolute pressure. This material wasdetermined by gas-liquid chromatographic techniques to consistpredominantly of linear butadiene trimers. The residue from thedistillation amounted to 5.2 grams.

An ultimate yield of percent at a conversion of 85 percent of3-methyl-1,4,6-heptatriene was obtained by the practice of thisinvention in this example.

Example H A mixture of 1.29 grams (0.02 mole) of n-butyllithium (used asa 15 percent by weight solution in n-hexane) and 50 milliliters ofn-pentane was cooled in an ice bath and contacted with 15 grams (0.28mole) of butadiene. Over a 30 minute period of time, the mixture wasallowed to warm to 25 C. at which time the mixture was added to 1.28grams (0.005 mole) of cobalt acetylacetonate in 25 milliliters ofn-pentane which had been cooled in an ice bath. The resulting brownreaction mixture was then allowed to warm to 25 C. The mixture was thencontacted with 207 grams (3.83 mols) of butadiene and the reactionmixture was allowed to stand at room temperature for 20 hours. Theunreacted butadiene was then vented and the amount of butadiene ventedwas 71 grams.

The remaining liquid material was contacted with a 5 weight percentaqueous solution of hydrochloric acid after which the organic phase wasseparated and distilled. The distillation yielded 77.1 grams of materialboiling from 61 to 75 C. at 125 millimeters mercury absolute pressurewhich was identified by gas-liquid chromatographic techniques to consistessentially of 31methyl-1,4,6-heptatriene.

This example of the invention gave an ultimate yield of3-methyl-1,4,5-heptatriene of 79.7 percent at 47 percent conversion.

Example III A catalyst was prepared by mixing 0.02 mole of nbutyllithiumwith 14 grams of butadiene in pentane at about 0 C. The mixture wasallowed to warm to room temperature over a period of 30 minutes. To thismixture was then added 5 millimoles of cobalt acetylacetonate and themixture was then cooled in an ice bath for 1 hour.

The resulting catalyst was then admixed with 287 grams of butadiene andmaintained in an ice bath for 6 hours. The mixture was then allowed towarm to 25 C. and maintained at this temperature for 60 hours. Thereactor was then vented releasing 68 grams of butadiene and theremaining liquid was hydrolyzed with a 5 weight percent aqueous solutionof hydrochloric acid. The organic layer was separated and distilled toyield 120.8 grams of material. This material was characterized asconsisting essentially of 3-methyl-1,4,6-heptatriene by gas-liquidchromatographic techniques.

This example gave an 86 percent ultimate yield of 3-methyl-l,4,6-heptatriene at the conversion of 49 percent.

A comparative run carried out by a process other than the process ofthis invention was made in which 1.29 grams of cobalt acetylacetonateand 144 grams of butadiene were charged to a 1-liter autoclave andcooled to Dry Ice temperature (-7=8 C.). At this time, 14 milliliters ofa 1.6 molar solution of triethylaluminum and cyclohexane was charged tothe autoclave. The autoclave was then heated to a temperature of 0 C. atwhich temperature the pressure was 0 p.s.i.g. The autoclave was thenheated to a temperature of from 60 to 65 C. and maintained in thattemperature range for 5 hours and 20 minutes during which time thepressure dropped from a maximum of 120 p.s.i.g. to 60 p.s.i.g. Theautoclave was then vented and the liquid material remaining distilledafter hydrolysis with a 5 weight percent aqueous solution ofhydrochloric acid. The distillation yielded 48.3 grams of3-methyl-1,4,6-heptatriene as determined by gas-liquid chromatographictechniques.

This comparative example gave a 42 percent ultimate yield at 79 percentconversion which is substantially less than Example I which was alsocarried out at 60 C. but which employed the catalyst of this inventionand thereby realized a 60 percent ultimate yield at an percentconversion. Thus, the use of the conjugated diene-organolithium adductin the catalyst of this invention effects a surprising improvement innot only the ultimate yield but also the conversion of butadiene to3-methyl-1,4,6- heptatriene in a shorter reaction time.

Another comparative run was carried out using 1.71 grams of dicobaltoctacarbonyl in 163 grams of butadiene which were charged to a 1-literautoclave and then cooled in an ice bath. Thereafter 94 milliliters of a1.6 molar solution of triethylaluminum in cyclohexane and an additionalgrams of butadiene were charged to the reactor. The reactor was thenheated to 40 C. at which time the pressure reached 50 p.s.i.g. Thereactor was maintained at 40 to 42 C. for 24 hours, during which timethere was no substantial pressure drop.

The reactor was vented and the liquid material remaining distilled afterhydrolysis with a 5 weight percent aqueous solution of hydrochloricacid. The distillate yielded 43.4 grams of 3-methyl-l,4,6-heptatrieneand 45 grams of higher boiling trienes and other oligomers, asidentified by gas-liquid chromatographic techniques.

This comparative example gave an ultimate yield of 3-methyl-1,4,6-heptatriene of 50 weight percent at 31 percent conversion.This is to be compared with Examples II and III which also employedtemperatures lower than 60 C. but obtained ultimate yields of 79.7percent at 47 percent conversion and 86 percent at 49 percentconversion, respectively.

Example IV A 7-ounce bottle was charged with about 16 milliliters ofn-hexane solution containing 1.6 grams of n-butyllithium and 50milliliters of ethyl ether. This solution was then cooled in an ice bathand charged with butadiene until grams was absorbed. The resultingmixture was then allowed to warm to room temperature (about 25 0.).

Another 7-ounce bottle was charged with 1.8 grams of nickelacetylacetonate in 25 milliliters of ethyl ether. After cooling in anice bath, the butyllithium solution prepared in the prior paragraph wasadded. The resulting mixture was stirred with continued cooling in theice bath for 1 hour and then allowed to warm to room temperature, forapproximately 2 hours.

At the end of the 2 hours warming period a 1-liter autoclave was flushedwith nitrogen and charged with the above-prepared catalyst together with120 grams of butadiene. The autoclave was then heated to 150 C. at whichtime the autoclave heaters were turned off. -At this time the pressurein the autoclave was 1-60 p.s.i.g. and after 1 hour and 22 minutes thetemperature had fallen to 98 C. and the pressure had dropped to 70p.s.i. The reaction mixture was hydrolyzed with a 10 weight percentsolution of hydrochloric acid after which the organic layer wasseparated, dried over calcium sulfate and stripped to remove lowerboiling materials. The stripped material was then distilled yielding91.8 grams of material boiling from 33 C. at 10 millimeters mercury to110 C. at 3 millimeters mercury absolute pressure. Analysis of thismaterial by gas-liquid chromatographic techniques indicated the presenceof 6.4 grams of 4-vinylcyclohexene, 3 grams of 1,5-cyclooctadiene, 79.1grams of 1,5,9-cyc1ododecatriene and 3.2 grams of an unidentifiedmaterial. The amount of residue from this distillation was 26.7 grams.This example gave an ultimate yield of cyclododecatriene of 72.8 percentat 90 p'ercent conversion.

Example V In this run 0.02 mole of n-butyllithium, 50 milliliters ofcyclohexane and 13 grams of butadiene were mixed and allowed to stand 4hours at room temperature (about 25 C.). The mixture was then added to acold (about 0 C.) suspension of 1.28 grams of nickel acetylacetonate in25 milliliters of cyclohexane. After 1.5 hours in an ice bath, thisresulting mixture was contacted with 330 grams butadiene in thefollowing manner.

A l-liter autoclave 'was flushed with nitrogen and charged with theabove-prepared catalyst and then 330 grams of butadiene. The autoclavewas then heated to 120 C. and maintained at this temperature for 1 hourand minutes during which time the pressure fell from a maximum 250p.s.i.g. to 60 p.s.i.g.

The autoclave was vented and the liquid material remaining washydrolyzed with a 10 weight percent aqueous solution of hydrochloricacid. The organic phase was then separated and distilled yielding 311.7grams of material boiling from 60 C. at 100 millimeters mercury absolutepressure to 120 C. at 3 millimeters mercury absolute pressure.Gas-liquid chromatographic analysis of this material indicated thepresence of 18.7 grams of 4-vinylcyclohexene, 14.0 grams of1,5-cyclooctadiene, and 279 grams of 1,5,9-cyclododecatriene. The amountof residue in this run was 16.6 grams.

This example gave a cyclododecatriene ultimate yield of 89 p'ercent at95 percent conversion. Thus, it can be seen that when in this examplethe butadiene and butyllithium were contacted for a longer period oftime prior to addition of a nickel compound a more active catalyst isformed as can be seen by comparing the ultimate yield of 72.8 percent at90 percent conversion for Example IV and the 89 percent ultimate yieldat percent conversion of this example.

In all the above examples, the ultimate yield was determined by dividingthe weight of desired dimer or trimer produced by the weight ofbutadiene consumed.

Example VI Butadiene and ethylene were converted to 1,4-hexadiene and2,4-hexadiene over a catalyst prepared from the adduct of butyllithiumand butadiene, and ferric acetylacetonate.

A 1.96 gram quantity of butyllithium, as a 14 weight percent solution inheptane, was diluted with 50 milliliters of n-pentane, cooled in an icebath, and treated with 14 grams of butadiene. This mixture was allowedto warm to room temperature, and after 30 minutes, was added to asuspension of 1.77 grams of ferric acetylacetonate in 25 milliliters ofn-pentane which had been cooled in an ice bath. This mixture was allowedto warm to room temperature before use.

The butadiene-ethylene conversion was carried out in an autoclave whichwas flushed with nitrogen, charged with the above-prepared catalyst,charged with 1'85 grams of butadiene, and then pressured with ethyleneto 450 p.s.i.g. which was maintained with stirring throughout thereaction. The reaction was continued for 6 hours with stirring at atemperature of about 25 C.

After the reaction period, the reaction mixture was hydrolyzed with 5weight percent aqueous hydrochloric acid, the organic phase separated,and the products identified by distillation, index of refraction, andgas-liquid chromatography. It was found that 98.6 grams of hexadieneswere produced from the run amounting to a 35-percent yield based onbutadiene. Of these hexadienes, 63.6 grams was cis-l,4-hexadiene while35 grams was 2,4-hexadicne.

Example V I'I In this example, the catalyst prepared from ferricchloride and the adduct of n-butyllithium and butadiene was used toconvert butadiene and ethylene to linear dienes.

The catalyst was prepared by charging a reactor with 7 grams of a, 14weight percent n-butyllithium in hexene solution together with 25milliliters of n-pentane. This mixture was cooled in an ice bath, andthen mixed with 10 grams of butadiene. The mixture was allowed to standovernight at room temperature. A solution of 0.81 gram of ferricchloride in 50 milliliters of ethyl ether was cooled in a Dry Iceacetone bath and treated with the above-prepared adduct. After one hourthe cold, brown solution was transferred to an autoclave. The autoclavewas then charged with 1 60 grams of butadiene and pressured to p.s.i.g.(at 15 C.) with ethylene.

The reaction was allowed to continue for about 3 hours at 40 to 65 C.and 100 to 275 p.s.i.g. At the completion of the reaction, the reactionmixture was hydrolyzed with 5 weight percent hydrochloric acid and theorganic phase was analyzed by gas-liquid chromatography. The analysisshowed the presence of 65.4 grams of cis 1,4-hexadiene and 1.9 grams of2,4-hexadiene for a total hexadiene yield of 23 percent.

Reasonable variations and modifications are possible within the scope ofthis disclosure without departing from the spirit and scope thereof.

I'claim:

1. A method of oligomerizing a conjugated diene selected from the groupconsisting of butadiene, isoprene, and piperylene comprising contactingat least one of said conjugated dienes under oligomerization conditionswith a catalyst consisting essentially of that formed on mixing anadduct formed from a conjugated diene selected from the group consistingof butadiene, isoprene and piperylene and an organolithium compound ofthe formula RLi wherein R is a radical selected from the groupconsisting of saturated aliphatic, saturated cycloaliphatic, aromatic,and combinations thereof having from 2 to 12 carbon atoms, inclusive,and x is a whole integer selected from the group 1, 2, and 3, a compoundselected from the group consisting of nickel halides, nickel salts ofmono-, di-, and tribasic organic acids containing from 2 to 20 carbonatoms per molecule, nickel chelates of beta-diketones of the formula RO()C-R 3 i ll wherein R is a radical selected from the group consisting ofsaturated aliphatic, saturated cycloaliphatic, aromatic, andcombinations thereof containing from 1 to 10 carbon atoms, inclusive,and nickel salts of dimethylglyoxime.

2. The method according to claim 1 wherein one of butadiene, isoprene,and piperylene are oligomerized employing an adduct formed by contactingbutadiene and said organolithium at a temperature in the range of fromabout 10 to about 80 C., using a ratio of moles of butadiene to molarequivalents of lithium in the range of 1/1 to 25/1, and wherein theadduct is contacted with the nickel compound at a temperature in therange of from about --80 to about 80 C. using from 2/1 to 6/1 molarequivalents of lithium per mole of nickel, the oligomerization iscarried out at a temperature in the range of from about 80 to about 200C.

3. The method according to claim 1 wherein butadiene is oligomerizedwith a catalyst consisting essentially of that formed on mixingbutadiene-butyllithium adduct with nickel acetylacetonate.

References Cited UNITED STATES PATENTS 3,219,716 11/1965 Wittenberg etal. 260-666 3,249,641 5/1966 Storrs et al 260666 FOREIGN PATENTS 618,6256/1962 Belgium. 1,329,122 4/1963 France.

DELBERT E. GANTZ, Primary Examiner.

V. OKEEFE, Assistant Examiner.

